The charges for traditional telephone services are postpaid, which means that the charges are billed after the telephone services have been provided. In other words, the familiar telephone bill that arrives each month includes charges for the previous month's telephone use. Telephone service providers, many of which serve millions of subscribers, therefore accrue enormous accounts receivable. Carrying such large accounts receivable incurs finance changes and reduces the company's liquidity. In addition, some portion of each month's accounts receivable go unpaid, as some subscribers default on their payments. Telephone service providers therefore have a financial motivation to encourage their subscribers to prepay for telephone service.
Other costly problems arise from the traditional telephone service policy of providing each subscriber in good standing with virtually unlimited credit for using telephone services. This means that at any time, any active subscriber account may be billed a virtually unlimited amount for using telephone services. Eventually, after a subscriber's account has been in arrears for several months, the subscriber's telephone service may be deactivated until the outstanding balance is paid. This unlimited credit policy may encourage undisciplined subscribers to incur imprudently large telephone bills. Worse yet, unlimited credit facilitates very large fraudulent telephone charges to subscriber accounts. To reduce the occurrence of unpaid and fraudulent telephone charges, telephone service providers are financially motivated to limit the amount of credit provided to subscribers.
Accordingly, many long distance and cellular telephone service providers have begun selling prepaid telephone service cards. These cards have a prepaid face value that may be redeemed by using telephone services provided by the issuer of the card. To encourage subscribers to use the prepaid cards, prepaid telephone service is often provided at a discount with respect to traditional postpaid service. Prepaid telephone service cards can also be used to increase sales and boost profits by providing new ways to package and sell telephone service. In particular, prepaid telephone service cards may be used as gifts and promotional items.
To support a prepaid telephone service card system, the telephone service provider must have a way to limit the value of the telephone service provided as a result of the use of the card to the value in the corresponding prepaid account. Of course, the balance in a prepaid account diminishes as telephone services are used. Eventually, the entire value of the prepaid account is exhausted. In the simple case, the prepaid account becomes exhausted between uses of telephone services, for example by cash redemption of the remaining balance. In this case, the telephone service provider simply does not honor the card after the value has been exhausted.
In the more challenging case, a prepaid account balance becomes exhausted while telephone service is being provided, for example in the middle of a cellular or long distance telephone call. Consider a card holder that uses a telephone prepaid card as a method of payment to initiate a cellular or long distance call. The telephone service provider honors the card because the corresponding account has a minimum threshold value. The card holder, however, may conduct very long telephone call, the cost of which far exceeds the prepaid account balance. The telephone service provider therefore needs a way to monitor the balance of the prepaid account while the telephone call is in progress and to disconnect the telephone call when the prepaid account balance is exhausted. Otherwise, a caller using a telephone prepaid card would effectively receive free telephone service after exhaustion of the prepaid account balance.
An inability to disconnect telephone services initiated with a prepaid telephone service card would expose the telephone service provider to a loss of revenue through the provision of some free service with each prepaid card. An unscrupulous person learning of this loophole could initiate a telephone call using a prepaid card with a small account balance and then maintain the connection for a virtually unlimited time. Distribution of a large number of telephone prepaid cards could therefore result in the provision of a large, unknown, and unknowable amount of free telephone service. In the extreme case, a large number of free telephone service could consume the available capacity in the telephone service provider's system, causing the provider further damage as subsequent would-be paying subscribers find the circuits busy. An inability to disconnect a telephone call initiated with a telephone prepaid card would therefore effectively prohibit a telephone service provider from offering telephone prepaid cards.
Long distance telephone service providers have therefore developed prepaid long distance telephone card systems with the ability to disconnect telephone calls initiated with telephone prepaid service cards. This type of system typically relies on an intelligent telephone service handling platform that a card holder accesses by dialing a special directory, such as a toll-free "800" directory number printed on the prepaid telephone service card. A voice channel communication (i.e., a communication using a voice channel or "trunk circuit") is then routed from the originating station to the intelligent platform, and then from the intelligent platform to the called station. The intelligent platform remains in the circuit to monitor the duration of the telephone call and to disconnect the telephone call, if necessary.
Like long distance telephone service providers, cellular telephone service providers also experience costly problems with postpaid accounts. Fraud by criminals who intercept the overhead data communications of cellular mobile radiotelephones and then use the purloined information to obtain cellular roaming service is a particularly costly crime. As a result, cellular telephone service providers have begun to issue prepaid cellular telephone service cards.
Prepaid cellular telephone service cards provide the card issuers with a number of advantages. For example, a prepaid telephone service card may be packaged for sale with a new cellular telephone to encourage the purchaser to select the issuer of the card as the purchaser's cellular telephone service provider. Alternatively, a goods or service provider could purchase a large number of prepaid telephone service cards having relatively small account balances and have the cards imprinted with advertising material for distribution to potential subscribers, such as patrons at a convention. There are many other potentially desirable uses for prepaid telephone service cards. A teenager away from home, for instance, could be given a prepaid telephone service card having a telephone service allowance with a fixed value. Similarly, a hotel or resort guest could be issued a cellular telephone with a prepaid account balance for use while staying at the hotel or resort as a guest.
Because conventional cellular switching equipment is not configured to rate telephone calls in real-time, a prepaid cellular telephone call is routed thorough a special voice-channel-connected intelligent platform that is configured to monitor, rate, and disconnect the telephone call, if necessary. In many cases, this has led cellular telephone service providers to set aside one or more groups of telephone numbers having a common prefix ("NPA-NXX") for prepaid accounts. A voice channel communication originating from or directed to a cellular telephone assigned one of these directory numbers is routed through an intelligent platform configured to implement the prepaid service. The intelligent platform remains in the circuit to monitor the duration of the telephone call and to disconnect the telephone call, if necessary. This approach consumes large blocks of directory numbers for prepaid accounts and does not allow a subscriber to use the same cellular telephone to place postpaid as well as prepaid telephone calls, which reduces the usefulness of the prepaid cellular telephone service cards as promotional items and gifts.
Conventional prepaid telephone service systems rely on two voice channel switching platforms, an originating switch and an intelligent platform configured to implement the prepaid service, to handle the originating end of a prepaid telephone call. A conventional postpaid telephone call, on the other hand, only requires one voice channel switching platform, the originating switch, to handle the originating end of a postpaid telephone call. Therefore, using the conventional prepaid systems to make prepaid and credit-limited telephone service generally available to cellular subscribers would virtually double the number of voice channel switching platforms required to originate telephone calls in the system. For this reason, the conventional prepaid systems may not be economically feasible alternatives for making prepaid telephone service generally available to cellular subscribers.
In addition, the conventional prepaid systems rely on "double-trunked" voice channel telephone circuits to complete many prepaid telephone calls. For example, in a typical cellular telephone system, a single intelligent platform, or a redundant pair of intelligent platforms in the same location, may implement a prepaid telephone service card system. To illustrate a "double-trunked" voice channel telephone circuit, consider a cellular system in which the intelligent platform is located in Atlanta. A telephone call originating in a cell served by a switch in Macon, and placed to a called party in Macon, will therefore be routed through the intelligent platform in Atlanta. Thus, a double-trunked voice channel circuit, Macon-to-Atlanta-to-Macon, is required to complete the prepaid telephone call. This type of double-trunked voice channel telephone circuit inefficiently loads the long distance voice channel trunks.
Moreover, many cellular telephone service customers subscribe to advanced telephone services, such as voice mail, call forwarding, conference calling, and so forth. These advanced services typically require a telephone call involving the advanced services to be routed through an intelligent telephone service platform that implements the advanced services. These advanced-service telephone calls therefore involve a double-trunked voice channel telephone circuit to the intelligent telephone service platform. Because a prepaid telephone call is typically routed through a different intelligent platform, an additional double-trunked voice channel telephone circuit would be required to connect a prepaid telephone call having the advanced services. Due to the inefficiency of this type of communication routing, a subscriber's advanced services may simply not be unavailable for prepaid telephone calls in conventional telecommunications systems.
An unfortunate consequence of the unavailability of advanced services for prepaid cellular telephone calls is that many of a telephone service supplier's preferred customers, those that subscribe to advanced services and use them extensively, are discouraged from using prepaid telephone services. As a result, prepaid and credit-limited services are not generally available to cellular subscribers, and there is no convenient way to provide subscribers of advanced services with effective incentives to prepay for their telephone service. In addition, there is no convenient way to limit the credit extended to these subscribers for using telephone services in a effort to minimize unpaid accounts and to prevent fraudulent charges to their accounts.
Thus, there is a need for an improved method an system for making prepaid and credit-limited telephone service generally available to cellular telephone service subscribers. Specifically, there is a need for a prepaid and credit-limited telephone service system that does not rely on special voice-channel-connected intelligent telephone call handling platforms. There is a further need to provide cellular telephone services in a manner that encourages cellular telephone service customers that subscribe to advanced services to prepay for telephone service and to limit the amount of credit that they are extended for using telephone services.